Add infrastructure needed to interpret, convert and search time.

What this change does is record the temporal units meta information
from the netcdfcf file into the database.  Now we can convert the
unitless timestamps given by netcdf into an absolute "days since
0-0-0" format (for comparison) and into Y-M-D format to present
to the user.

The database now records: the timesteps (as before), the units
(so you can convert at will) and the min and max times in absolute
and YMD formats.
NOTES:
1) The UI is not yet changed and looks and works just like before.
2) The converter python module functions OK now now but it should
be converted into an interface into cfunits for better fidelity.
3) Requires a corresponding VTK change to get the units back.
fix commit late induced typos
fix data path to do better than clt.nc and add units

get spatial bounds and array ranges and units into mongo
get temporal units and add stub that normalizes them (internals of
  which are intended to be replaced by udunits) so that we can
  interpret what times mean
wrap last to first point values to create missing implicit cell
wrap lats into -180..180
render in < 32000 point chunks for webGL limit and use cross chunk
  scalar ranges for colormaps
deal with mask values by turning them into NaNs and handling them
  in a javascript friendly way
Merge remote-tracking branch 'origin/normalize_time'

* origin/normalize_time:
  fix data path to do better than clt.nc and add units
  fix commit late induced typos
  Add infrastructure needed to interpret, convert and search time.

Conflicts:
	web/apps/archive/archive.js
Misc fixes
Removed debug messages
Merge remote-tracking branch 'origin/normalize_time_semi_merged'

* origin/normalize_time_semi_merged:
  Removed debug messages
  Misc fixes
  fix data path to do better than clt.nc and add units
  fix commit late induced typos
  Add infrastructure needed to interpret, convert and search time.